This invention relates to equipment and methods for protecting apparatus from over-voltage and over-current conditions and is particularly directed to sensitive devices attached to electrical conductors serving various types of apparatus such as used for communication. An example of the protection device's application is the device protecting apparatus from the effects of excessive voltage or current such as might occur because of lightning, a fault, contact by a high tension line and the like.
Of the various types of equipment presently employed for accomplishing the foregoing, each suffers from one or more disadvantages including excessive cost and size, lack of adaptability to existing protector terminals, maintenance difficulties, hazardous conditions during servicing, loss of function in the presence of sustained overload, lack of safety provision thereby permitting the apparatus supposedly under protection to function without a protector, inability to protect apparatus from both high voltage surges and low level voltages which cause sustained currents, and less-than-optimum reliability.
It is an object of this invention to overcome or substantially reduce the foregoing shortcomings and to this end the invention provides improvements in performance, utilization and construction leading to reduction in size and cost, adaptability to existing mounting locations, reduction in hazards, an assurance that the over-voltage protector is installed, ability to utilize the device in a densely packaged area, simplification and safety in servicing, ability to provide protection from both excessive voltage and excessive current, and an increase in reliability. Moreover, in the invention techniques, additional protection features are attained without significantly impairing the essential simplicity of the construction.
The invention consists of the novel methods, processes, parts, steps, combinations and improvements herein shown and described.